Kolkata, May 13 (UNI) Ionizing radiation is a type of energy released by atoms that travels in the form of electromagnetic waves (gamma or X-rays) or particles (neutrons, beta or alpha).
According to the World Health Organization (WHO), The spontaneous disintegration of atoms is called radioactivity and the excess energy emitted is a form of ionizing radiation. Unstable elements which disintegrate and emit ionizing radiation are called radionuclides.
All radionuclides are uniquely identified by the type of radiation they emit, the energy of the radiation, and their half-life.
The activity — used as a measure of the amount of a radionuclide present — is expressed in a unit called the becquerel (Bq): one becquerel is one disintegration per second. The half-life is the time required for the activity of a radionuclide to decrease by decay to half of its initial value.
The half-life of a radioactive element is the time that it takes for one half of its atoms to disintegrate. This can range from a mere fraction of a second to millions of years (e.g. iodine-131 has a half-life of 8 days while carbon-14 has a half-life of 5730 years).
People are exposed to natural radiation sources as well as human-made sources on a daily basis. Natural radiation comes from many sources including more than 60 naturally-occurring radioactive materials found in soil, water and air.
Radon, a naturally-occurring gas, emanates from rock and soil and is the main source of natural radiation. Every day, people inhale and ingest radionuclides from air, food and water.
People are also exposed to natural radiation from cosmic rays, particularly at high altitude. On average, 80 per cent of the annual dose of background radiation that a person receives is due to naturally occurring terrestrial and cosmic radiation sources.
Background radiation levels vary geographically due to geological differences. Exposure in certain areas can be more than 200 times higher than the global average.
Human exposure to radiation also comes from human-made sources ranging from nuclear power generation to medical uses of radiation for diagnosis or treatment. Today, the most common human-made sources of ionizing radiation are medical devices, including X-ray machines.
Radiation exposure may be internal or external, and can be acquired through various exposure pathways.
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